High School

The SAT verbal test has a population mean of 500 and a population standard deviation of 100.
Fifty students at the University of Idaho are sampled and they report an average SAT verbal score of 535.
An institutional researcher would like to determine if the UI students have a significantly higher mean on the SAT verbal test.
What statistical test would be used?
A. repeated measures t-test
B. z-score test statistic
C. ANOVA
D. one sample t-test

Answer :

The correct option is option (B).
For the given scenario B) z-score test statistic would be used.

To determine if the University of Idaho students have a significantly higher mean on the SAT verbal test compared to the known population mean, we would use a z-score test statistic, specifically a one-sample z-test.

Here's why the one-sample z-test is the appropriate choice:
1. The population standard deviation is known to us (100), which allows us to use the z-test instead of the t-test. The t-test is typically utilized when the population standard deviation is unknown and must be estimated using the sample standard deviation.

2. We have a single sample of interests (the 50 students from the University of Idaho) and a single population mean to compare this sample against (the known population mean of 500). This points to a one-sample test rather than something like ANOVA or a repeated measures test, which would be used for comparisons involving more than two groups or paired data.

3. The sample size is greater than 30 (n = 50), which suggests that the distribution of sample means is likely to be normally distributed due to the Central Limit Theorem. This justifies using the z-test.

4. Our goal is to determine if there is a significant difference in means, specifically checking if the University of Idaho students score higher than the population mean. This identifies the use of a test statistic that compares a sample mean to a known population mean, again supporting the one-sample z-test.

Given this information, the correct statistical test for this scenario is: B. z-score test statistic